kasan: refactor pcpu kasan vmalloc unpoison

commit 6f13db031e27e88213381039032a9cc061578ea6 upstream.

A KASAN tag mismatch, possibly causing a kernel panic, can be observed
on systems with a tag-based KASAN enabled and with multiple NUMA nodes.
It was reported on arm64 and reproduced on x86. It can be explained in
the following points:

1. There can be more than one virtual memory chunk.
2. Chunk's base address has a tag.
3. The base address points at the first chunk and thus inherits
   the tag of the first chunk.
4. The subsequent chunks will be accessed with the tag from the
   first chunk.
5. Thus, the subsequent chunks need to have their tag set to
   match that of the first chunk.

Refactor code by reusing __kasan_unpoison_vmalloc in a new helper in
preparation for the actual fix.

Link: https://lkml.kernel.org/r/eb61d93b907e262eefcaa130261a08bcb6c5ce51.1764874575.git.m.wieczorretman@pm.me
Fixes: 1d96320f8d53 ("kasan, vmalloc: add vmalloc tagging for SW_TAGS")
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: Kees Cook <kees@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index dcbd8b09680e05da3b9b66296103219176539c45..4a54449dbfad8ffabe550cd5a410e71894e86b6f 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -608,6 +608,16 @@ static __always_inline void kasan_poison_vmalloc(const void *start,
                __kasan_poison_vmalloc(start, size);
 }
 
+void __kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                                kasan_vmalloc_flags_t flags);
+static __always_inline void
+kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                         kasan_vmalloc_flags_t flags)
+{
+       if (kasan_enabled())
+               __kasan_unpoison_vmap_areas(vms, nr_vms, flags);
+}
+
 #else /* CONFIG_KASAN_VMALLOC */
 
 static inline void kasan_populate_early_vm_area_shadow(void *start,
@@ -632,6 +642,11 @@ static inline void *kasan_unpoison_vmalloc(const void *start,
 static inline void kasan_poison_vmalloc(const void *start, unsigned long size)
 { }
 
+static __always_inline void
+kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                         kasan_vmalloc_flags_t flags)
+{ }
+
 #endif /* CONFIG_KASAN_VMALLOC */
 
 #if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index ed4873e18c75c90c6227f7a0faf5c1788cf52e62..7c66d5445cf5d8447d69130170a0e85dd3bb9671 100644 (file)
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -28,6 +28,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/bug.h>
+#include <linux/vmalloc.h>
 
 #include "kasan.h"
 #include "../slab.h"
@@ -559,3 +560,19 @@ bool __kasan_check_byte(const void *address, unsigned long ip)
        }
        return true;
 }
+
+#ifdef CONFIG_KASAN_VMALLOC
+void __kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                                kasan_vmalloc_flags_t flags)
+{
+       unsigned long size;
+       void *addr;
+       int area;
+
+       for (area = 0 ; area < nr_vms ; area++) {
+               size = vms[area]->size;
+               addr = vms[area]->addr;
+               vms[area]->addr = __kasan_unpoison_vmalloc(addr, size, flags);
+       }
+}
+#endif

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 6870e030f9a78dc19e168c75527583187948028b..98e3671e946720674a45d3e35626ea1b08742cac 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4812,9 +4812,7 @@ retry:
         * With hardware tag-based KASAN, marking is skipped for
         * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
         */
-       for (area = 0; area < nr_vms; area++)
-               vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr,
-                               vms[area]->size, KASAN_VMALLOC_PROT_NORMAL);
+       kasan_unpoison_vmap_areas(vms, nr_vms, KASAN_VMALLOC_PROT_NORMAL);
 
        kfree(vas);
        return vms;